Communications Errors - Omron E5ZE Operation Manual

Communications Errors

4-2 Communications Errors
Communications Not Possible or No Response
Communications Baud rate of the E5ZE is different from that of
conditions the host device.
Communications method of the E5ZE is different
from that of the host device.
Connections
Excessive number of E5ZE Units are connected
in parallel.
Transmission path is too long.
Same unit number has been assigned more than
once on the same transmission path.
Communications data error due to ambient
noise.
Mistake in the use of the Optical Interface and
Link Adapter Units.
4. Troubleshooting Based on Error Symptoms
If the cause of the error is still unknown after checking all the previously men-
tioned items, find the cause by isolating the symptoms of the error while re-
ferring to the tables in this section, and remedy accordingly.
Probable cause Remedy
Set the same rate.
Set the host device's communications conditions
as follows:
• Stop bits:
2
• Parity:
Even
• Bit length: 7 bits
Do not connect an excessive number of E5ZE
Units.
• Do not connect the host device directly to more
than one E5ZE through RS-232C
communications.
• The number of E5ZE Units that can be
connected to the host device for RS-422 or
RS-485 communications is 16 max.
The transmission path must be within the
permissible range.
• The maximum RS-232C transmission path is
15 m.
• The maximum RS-422 or RS-485 transmission
path is 500 m in total.
Make sure that different numbers are assigned
to all the E5ZE Units that communicate with the
host device.
• Move the communications cable away from the
source of noise.
• Use shielded communication cables.
• Use an Optical Interface.
• Write a program that makes it possible for the
host device to detect a response error for any
command that the host device transmits and to
re-transmit it again.
Refer to the datasheets of the Optical Interface
and Link Adapter Units used.
Section 4-2
49